Sending Message through JavaFX GUI

Hello everyone so I am developing an app that is capable to send a message to a certain number through my API client using Nexmo. In my UsersController that I use to send the text message from it gives me an error when I run it saying:

Caused by: javafx.fxml.LoadException: 
/C:/Users/man/workspace/DatabaseProgramm/target/classes/fxml/User.fxml:9

and

Caused by: java.lang.ClassNotFoundException: UsersController

I have the UsersController class defined as follows:

//Necessary imports 
public class UsersController implements Initializable
{
    @FXML 
    public static TextField txtTo;
    @FXML 
    public static TextField txtMessage;
    @FXML 
    public Button btnSend;

    @Override
    public void initialize(URL location, ResourceBundle resources)
    {
        try
        {
            String getTo = txtTo.getText();
            String getMsg = txtMessage.getText();
            AuthMethod auth = new TokenAuthMethod("api_key", "api_id");
            NexmoClient client = new NexmoClient(auth);
            TextMessage text = new TextMessage("12013514464", getTo, getMsg);

            btnSend = new Button();


        }catch(Exception e){}
    }

    @FXML 
    private void sendMessage() throws IOException, NexmoClientException
    {
        AuthMethod auth = new TokenAuthMethod("api_key", "api_id");
        NexmoClient client = new NexmoClient(auth);

        TextMessage text = new TextMessage("12013514464", "+12063760671", "YIKES");
        SmsSubmissionResult[] responses = client.getSmsClient().submitMessage(text);
        for(SmsSubmissionResult response : responses)
        {
            System.out.println(response);
        }

    }

}

In the Users.xml file I have the controller set to the Users controller:

<AnchorPane prefHeight="401.0" prefWidth="506.0" style="&#10;" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" fx:controller="UsersController">

Why is java saying that there is an error on the above line, and it states that there is no class UsersController? Help on this would be fantastic!